Excel files extremely slow open on network from 2nd file onward

[I realize I'm necrobumping, but this thread comes up on web searches, so resolving the issue might be helpful to others]

The issue should occur only when opening the subsequent files from Explorer. If the subsequent files are opened from within Excel (File / Open), they should open as fast as the first file. If this is accurate, the issue is with the Dynamic Data Exchange (DDE) protocol and can be fixed by modifying two registry entries:

• HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\Open\ddeexec
• HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\Open\ddeexec

If you are having the issue, I suspect these entries are blank. Set them to [open("%1" /ou "%u")] (include everything just as it appears, including brackets).

Here are references so that you don't have to trust a random cletus on the internet. I can't post links because my account is too new (a silly requirement), but if you Google these phrases exactly and with quotes, the articles with the quoted name will show up:

• "Excel Opens 2nd / Subsequent File from Explorer Slowly but within Excel Quickly" (should be the first result...it's a Microsoft Answers post, but in this case it's quite useful)
• "Excel slow to open second (or subsequent) file" (might be the second result, with the above reference being the first...it's a Microsoft Learn post)

The second reference is worth reading because it add similar fixes for .xlsm, .xlsb, and .csv files. Yes, each extension has its own registry cell. Typical Microsoft cruft. Grab a *nix and save a penguin, pufferfish, or dogcow, depending on flavor.

[removing duplicate post -- my first submission returned an error, but apparently it actually worked]